Displacement sensor and 3D printer

Abstract

The utility model relates to a displacement sensor and a 3D printer, and the displacement sensor comprises an eddy current sensing unit which is connected with a processor of the 3D printer; the magnetic conductivity of the magnetic conduction unit is larger than that of air, and the eddy current sensing unit is arranged on one side of the magnetic conduction unit; and the magnetization unit is arranged on one side, far away from the eddy current sensing unit, of the magnetic conduction unit and magnetizes the magnetic conduction unit. According to the displacement sensor, the magnetization unit is arranged on the side, away from the eddy current sensing unit, of the magnetic conduction unit, and the magnetic conduction unit is magnetized through the magnetization unit, so that the magnetic flux of the magnetic conduction unit can be increased, the magnetic field around the eddy current sensing unit is enhanced, the measurement sensitivity of the displacement sensor is improved, and the measurement range is widened.

Description

Technical Field

[0001] This application relates to the field of 3D printing technology, and more particularly to a displacement sensor and a 3D printer. Background Technology

[0002] When an eddy current displacement sensor moves relative to a metal sample, changes in the eddy currents formed in the metal cause changes in the sensor's output signal. By acquiring these changes in the output signal, the distance between the sensor and the metal sample can be calculated. However, existing eddy current displacement sensors have relatively low sensitivity and a small measurement range. Utility Model Content

[0003] To address the aforementioned problems, this application provides a displacement sensor suitable for 3D printers. By incorporating a magnetization unit into the displacement sensor to magnetize the magnetic permeable unit, the magnetic flux of the magnetic permeable unit is increased, thereby amplifying the output signal of the displacement sensor and improving its measurement sensitivity and expanding its measurement range. Furthermore, this application also provides a 3D printer equipped with this displacement sensor, specifically including the following solution:

[0004] In a first aspect, this application provides a displacement sensor suitable for a 3D printer, the 3D printer including a processor. The displacement sensor includes: an eddy current sensing unit connected to the processor of the 3D printer;

[0005] A magnetic permeable unit, the magnetic permeability of which is greater than that of air, and an eddy current sensing unit is provided on one side of the magnetic permeable unit;

[0006] The magnetization unit is located on the side of the magnetic conductive unit away from the eddy current sensing unit, and the magnetic conductive unit is magnetized.

[0007] The displacement sensor provided in this application incorporates an eddy current sensing unit to generate an eddy current effect. This eddy current sensing unit can sense changes in the external magnetic field and convert these changes into changes in electrical signals. By providing a magnetically conductive unit on one side of the eddy current sensing unit, and because the magnetic permeability of the magnetically conductive unit is greater than that of air, the magnetic field lines of the eddy current sensing unit can be guided by the magnetically conductive unit, resulting in a more concentrated magnetic field line and thus enhancing the eddy current effect.

[0008] Furthermore, this application increases the magnetic flux of the magnetically conductive unit by setting a magnetization unit on the side of the magnetically conductive unit away from the eddy current sensing unit, and magnetizing the magnetically conductive unit with the magnetization unit, thereby enhancing the magnetic field around the eddy current sensing unit. A strong magnetic field can sense weak external magnetic fields; that is, within a certain range, the stronger the magnetic field, the stronger the sensing ability of the eddy current sensing unit to sense the object under test. Alternatively, it can be understood that an increase in magnetic flux causes a larger change in magnetic flux for the same displacement, thus generating a larger electrical signal. Therefore, when a magnetic or metallic object under test (such as the nozzle of a 3D printer) approaches the displacement sensor, the strong magnetic field of the eddy current sensing unit can respond quickly, thereby improving the measurement sensitivity of the displacement sensor provided in this application. Simultaneously, because the eddy current sensing unit's sensing ability to sense the object under test is enhanced, even if the distance between the displacement sensor and the object under test is large, the displacement sensor can obtain a larger signal amplitude, thus expanding the measurement range of the displacement sensor provided in this application. For example, the magnetization unit can make the magnetic permeability unit in a magnetic saturation state. This magnetic saturation state is the stage where the magnetic permeability of the magnetic permeability unit changes drastically when the external magnetic field changes. At this time, the drastic change in magnetic permeability leads to a large change in the electrical signal output by the eddy current sensing unit, which can improve the sensitivity of the displacement sensor.

[0009] In one embodiment, a displacement sensor is fixed to the printing platform of the 3D printer, and the displacement sensor is used to detect the nozzle of the 3D printer located above the printing platform.

[0010] In the vertical direction, the minimum distance between the eddy current sensing unit and the nozzle is greater than the minimum distance between the magnetic guiding unit and the nozzle, but less than the minimum distance between the magnetizing unit and the nozzle.

[0011] In this embodiment, by fixing the displacement sensor to the printing platform of the 3D printer, the eddy current sensing unit of the displacement sensor can generate an eddy current magnetic field on the nozzle, which in turn can affect the original magnetic field of the eddy current sensing unit, since the nozzle of the 3D printer is made of a conductive and magnetically permeable material. When the nozzle moves relative to the displacement sensor, the eddy current magnetic field changes with the displacement of both, and the original magnetic field changes with the change of the eddy current magnetic field, causing a change in the electrical signal, thereby realizing the displacement detection of the nozzle relative to the printing platform. This application sets the minimum distance between the eddy current sensing unit and the nozzle to be less than the minimum distance between the magnetization unit and the nozzle, that is, sets the eddy current sensing unit closer to the nozzle than the magnetization unit. At the same time, it sets the minimum distance between the eddy current sensing unit and the nozzle to be greater than the minimum distance between the magnetically permeable unit and the nozzle, that is, sets the eddy current sensing unit to be housed in the magnetically permeable unit, avoiding the eddy current sensing unit from being easily contaminated or damaged by external foreign objects, and avoiding the nozzle of the 3D printer from colliding with the eddy current sensing unit.

[0012] In one embodiment, the magnetic guiding unit includes a magnetic guiding block, the eddy current sensing unit includes a detection coil, the magnetic guiding block has a receiving groove with the opening of the receiving groove facing the nozzle, and the detection coil is received in the receiving groove.

[0013] In this embodiment, a magnetically conductive block is used in the magnetically conductive unit to guide magnetic lines of force, and a detection coil is used in the eddy current sensing unit to sense changes in the magnetic field and convert them into changes in electrical signals. By incorporating a receiving groove in the magnetically conductive block to house the detection coil, the detection coil can be protected from contamination or damage caused by external objects or collisions, thus preventing it from affecting detection. Furthermore, the magnetically conductive block can concentrate the magnetic lines of force around the detection coil, preventing the magnetic field energy of the detection coil from leaking into the air, which is beneficial for improving the detection sensitivity of the displacement sensor.

[0014] In one embodiment, the magnetic permeability of the magnetic permeable unit changes drastically when the external magnetic field changes.

[0015] In this embodiment, the permeability of the magnetically conductive unit changes drastically when the external magnetic field changes, meaning the magnetically conductive unit tends to be magnetically saturated or in a magnetically saturated state under the magnetization effect of the magnetization unit. Since the permeability of the magnetically conductive unit in a magnetically saturated state is at its limit, the magnetization intensity of the magnetically conductive unit no longer increases linearly with the magnetic field strength, but enters the nonlinear response region. When the displacement sensor is relatively close to the object under test, the object under test is magnetized, and the feedback magnetic field generated by its own magnetization is superimposed on the original magnetic field of the magnetically conductive unit. Because the magnetically conductive unit is already in a magnetically saturated state, the additional feedback magnetic field causes the permeability of the magnetically conductive unit to decrease sharply, which in turn causes the inductance of the eddy current sensing unit to decrease rapidly, thus significantly increasing the oscillation frequency of the eddy current sensing unit. Therefore, a small displacement change between the displacement sensor and the object under test can be converted into a large change in permeability, further converted into a significant frequency change, forming a nonlinear amplification effect to amplify the output signal of the displacement sensor, thereby further improving the measurement sensitivity and expanding the measurement range of the displacement sensor provided in this application.

[0016] In one embodiment, the receiving groove is filled with insulating adhesive, which at least covers the detection coil.

[0017] In this embodiment, by placing insulating glue in the receiving groove and wrapping it around the detection coil, the detection coil can be fixed and also be insulated and protected.

[0018] In one embodiment, a positioning post is provided in the receiving groove, the positioning post extends in the vertical direction, and the detection coil is sleeved on the positioning post.

[0019] In this embodiment, by setting a positioning post in the receiving groove, the positioning post can pre-position the detection coil, which is beneficial for the installation of the displacement sensor.

[0020] In one embodiment, the displacement sensor includes a transmission line connected between a detection coil and a processor.

[0021] In this embodiment, the detection coil and the processor are connected by a transmission line, which facilitates the transmission of the electrical signal from the detection coil to the processor, which can then calculate the distance between the object under test and the displacement sensor based on the electrical signal.

[0022] In one embodiment, the magnetic block includes a wiring groove that communicates with a receiving groove, and a transmission line is disposed in the wiring groove.

[0023] In this embodiment, by providing a wiring groove communicating with the receiving slot on the magnetic block, it is beneficial to fix and protect the transmission line, while also reducing the size of the displacement sensor. For example, the wiring groove extends through the width of the magnetic block; providing a wiring groove extending through the magnetic block in that direction helps to shorten the transmission distance of the transmission line and improve transmission efficiency.

[0024] In one embodiment, the wiring channel is provided with filler adhesive, which at least covers the transmission line.

[0025] In this embodiment, by placing filler adhesive in the cable tray and wrapping it around the transmission line, the transmission line can be fixed and protected.

[0026] In one embodiment, the displacement sensor includes a circuit board disposed on the side of the magnetization unit away from the magnetic conduction unit; a detection coil is connected to the circuit board via a transmission line, and the circuit board is connected to the processor.

[0027] In this embodiment, a circuit board is provided to process the electrical signal of the detection coil and transmit it to the processor so that the processor can calculate the distance between the object under test and the displacement sensor.

[0028] In one embodiment, the difference between the distance between the magnetically conductive unit and the nozzle and the distance between the detection coil and the nozzle is less than the diameter of the detection coil.

[0029] In this embodiment, the difference between the distance between the magnetic guiding unit and the nozzle and the distance between the detection coil and the nozzle is less than the diameter of the detection coil. This means the distance between the end face of the detection coil facing the nozzle and the opening of the receiving groove of the magnetic guiding block is limited to less than the diameter of the detection coil. This prevents the detection coil from being embedded too deeply in the magnetic guiding block, which would result in a large magnetic field distance between the detection coil and the nozzle, affecting the detection effect. Furthermore, it prevents the detection coil from being exposed outside the magnetic guiding block, thus avoiding leakage of the magnetic field lines into the air and affecting the detection sensitivity.

[0030] In one embodiment, the material of the magnetically conductive unit includes at least one of ferrite, soft magnetic material, hard magnetic material, metallic magnetic material, and powder magnetic material.

[0031] In this embodiment, based on the high magnetic permeability of ferrite, this application utilizes ferrite to fabricate a magnetically conductive unit, which can effectively guide and concentrate magnetic field lines, thereby improving the measurement sensitivity of the displacement sensor provided by this application.

[0032] In one embodiment, the magnetization unit includes a first permanent magnet.

[0033] In this embodiment, based on the fact that the permanent magnet itself has a magnetic field, this application provides a first permanent magnet in the magnetization unit to ensure that the magnetization unit can magnetize the magnetic conductive unit.

[0034] In one embodiment, the magnetization unit includes a first electromagnet.

[0035] In this embodiment, based on the fact that an electromagnet can generate a magnetic field after being energized, and that the magnitude and direction of the magnetic field can be adjusted by changing the magnitude and direction of the current, this embodiment of the application sets a magnetization unit including a first electromagnet to ensure that the magnetization unit can magnetize the magnetic conduction unit. At the same time, the magnetization effect on the magnetic conduction unit can be controlled by adjusting the magnetic field of the magnetization unit.

[0036] In one embodiment, the object to be tested includes a magnetically conductive material.

[0037] In this embodiment, based on the magnetic permeability of the magnetic material, this application sets the object under test as a magnetic permeable material. When the displacement sensor moves relative to the object under test, the magnetic field around the eddy current sensing unit can magnetize the object under test, so that the object under test forms a feedback magnetic field. The feedback magnetic field of the object under test can in turn affect the magnetic field of the eddy current sensing unit, thereby realizing displacement detection.

[0038] In one embodiment, the object to be tested includes a second permanent magnet.

[0039] In this embodiment, based on the magnetic field inherent in the permanent magnet itself, this application sets a second permanent magnet in the object under test to ensure that the object under test can affect the magnetic field of the eddy current sensing unit when it is close to the displacement sensor, thereby realizing displacement detection.

[0040] In one embodiment, the object to be tested includes a second electromagnet.

[0041] In this embodiment, based on the fact that an electromagnet can generate a magnetic field when energized, and that the magnitude and direction of the magnetic field can be adjusted by changing the magnitude and direction of the current, this embodiment of the application sets the object under test to include a second electromagnet to ensure that the object under test can affect the magnetic field of the eddy current sensing unit.

[0042] In one embodiment, the magnetic field direction of the magnetization unit is the same as the magnetic field direction of the object under test.

[0043] In this embodiment, by setting the magnetic field direction of the magnetization unit to be the same as the magnetic field direction of the object under test, when the displacement sensor and the object under test are relatively close, the magnetic field of the magnetization unit and the magnetic field of the object under test can be superimposed to a large extent to enhance the magnetic field strength around the eddy current sensing unit, thereby causing the permeability of the magnetic permeable unit to drop sharply.

[0044] In one embodiment, the positioning post and the magnetic block are an integral structure.

[0045] In this embodiment, the positioning post and the magnetic block are integrated into one structure, which simplifies the installation of the displacement sensor and also enables the positioning of the detection coil by the positioning post.

[0046] Secondly, this application provides a 3D printer that includes a processor, a nozzle, a printing platform, and a displacement sensor as described in any of the above embodiments, wherein the processor is electrically connected to the displacement sensor.

[0047] It is understood that the 3D printer of the second aspect of this application, because it uses the displacement sensor provided in the first aspect of this application, also has all the beneficial effects that can be obtained in any embodiment provided in the first aspect of this application. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a schematic diagram of the structure of a 3D printer provided in one embodiment of this application;

[0050] Figure 2 This is an exploded structural diagram of a displacement sensor provided in one embodiment of this application;

[0051] Figure 3 This is a schematic diagram of the displacement sensor provided in one embodiment of this application, viewed from one side.

[0052] Figure 4 This is a graph showing the relationship between the magnetic permeability and the magnetic field strength of a magnetically conductive unit provided in one embodiment of this application.

[0053] Figure 5 This is a schematic diagram of the assembly structure of the printing platform and displacement sensor provided in one embodiment of this application;

[0054] Figure 6This is an exploded structural diagram of the printing platform and displacement sensor provided in one embodiment of this application;

[0055] Figure 7 This is an exploded structural diagram of the displacement sensor provided in another embodiment of this application.

[0056] Reference numerals: 200-3D printer; 201-guide component; 202-nozzle; 203-printing platform; 204-processor; 100-displacement sensor; 10-eddy current sensing unit; 11-detection coil; 20-magnetic guiding unit; 21-magnetic guiding block; 211-receiving groove; 212-positioning post; 213-wiring groove; 30-magnetizing unit; 40-fixed base; 41-mounting groove; 50-protective film; 60-circuit board. Detailed Implementation

[0057] To facilitate understanding of this application, a more comprehensive description will be provided below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of this application.

[0058] The following descriptions of the embodiments are based on the accompanying illustrations and are used to illustrate specific embodiments in which this application can be implemented. The component designations used herein, such as "first," "second," etc., are merely for distinguishing the described objects and have no sequential or technical meaning. Unless otherwise specified, the terms "connection" and "linkage" used in this application include both direct and indirect connections (linkages). Directional terms used in this application, such as "up," "down," "front," "rear," "left," "right," "inner," "outer," "side," etc., are merely for reference to the accompanying illustrations. Therefore, the use of directional terms is for better and clearer explanation and understanding of this application, and does not indicate or imply that the referred device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this application.

[0059] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joint" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising," "may include," "include," or "may include" used in this application indicate the presence of the corresponding disclosed function, operation, element, etc., and do not limit one or more other functions, operations, elements, etc. Moreover, the terms "comprising" or "include" indicate the presence of the corresponding features, number, steps, operations, elements, components, or combinations thereof disclosed in the specification, but do not exclude the presence or addition of one or more other features, number, steps, operations, elements, components, or combinations thereof, and are intended to cover non-exclusive inclusion.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0061] Please refer to the above. Figure 1 , Figure 1 This is a schematic diagram of the structure of a 3D printer 200 provided in one embodiment of this application.

[0062] like Figure 1 As shown, the 3D printer 200 provided in this application includes a guide 201, a nozzle 202, and a printing platform 203. In some embodiments, the 3D printer 200 is a gantry structure. The guide 201 can be supported by two vertical columns along the Z-axis and can move up and down along the Z-axis. The nozzle 202 is disposed on the tool head of the 3D printer 200 and can move relative to the guide 201 along the Y-axis with the tool head. The printing platform 203 is disposed below the tool head. The tool head is used to move relative to the printing platform 203 along a preset trajectory and extrudes printing material towards the printing platform 203 through the nozzle 202. The printing platform 203 is used to carry the printing material extruded by the nozzle 202 to facilitate the formation of a printed model. To obtain good printing results, the nozzle 202 needs to be offset calibrated. Therefore, the 3D printer 200 provided in this application also includes a displacement sensor 100 for detecting the nozzle 202 located above the printing platform 203.

[0063] In one embodiment, the 3D printer includes a processor ( Figure 1 (Not shown in the diagram) The processor is electrically connected to the displacement sensor 100 and receives the output signal from the displacement sensor 100. The displacement sensor 100 is fixed to the printing platform 203 of the 3D printer, specifically positioned at the rear center of the printing platform 203. The nozzle 202 can move relative to the printing platform 203 along any of the X, Y, or Z axes. The displacement sensor 100 detects the position of the nozzle 202 relative to the printing platform 203 and provides an output signal to the processor. The processor receives the output signal from the displacement sensor 100 and determines the current position of the nozzle 202. The processor also calculates the offset of the nozzle 202 relative to a preset position and transmits a drive signal to the drive mechanism of the 3D printer 200. This allows the drive mechanism of the 3D printer 200 to drive the tool head, thereby moving the nozzle 202 to compensate for the offset and achieve nozzle 202 offset calibration.

[0064] In one embodiment, the displacement sensor 100 can be used to detect the displacement of the nozzle 202 relative to the printing platform 203 along the Z-axis direction. In other embodiments, the displacement sensor 100 can be used to detect the displacement of the nozzle 202 relative to the printing platform 203 along the X-axis or Y-axis direction. This application does not make any particular limitation on this.

[0065] It should be noted that fixing the displacement sensor 100 to the printing platform 203 in the above embodiment is only an example. In other embodiments, the displacement sensor 100 can be fixed to the tool head or other components that are relatively fixed to the nozzle 202, which can also achieve the detection of the relative displacement between the nozzle 202 and the printing platform 203. Furthermore, the displacement sensor 100 can not only be used for nozzle 202 calibration, but also for detecting the relative distance between any two components. That is, the displacement sensor 100 includes, but is not limited to, applications for nozzle 202 calibration in 3D printers.

[0066] Figure 1 The 3D printer 200 shown should be understood as an example. The 3D printer 200, including the displacement sensor 100 provided in this application, can also have other structures, such as a corexy structure or a cantilever structure. It is foreseeable that 3D printers with other structures can also achieve the effects described in this application, which will not be elaborated here. That is, this application does not limit the structure of the 3D printer 200.

[0067] Please refer to the above. Figure 2 , Figure 2 This is an exploded structural diagram of the displacement sensor 100 provided in one embodiment of this application; Figure 3 This is a structural schematic diagram of one side of the displacement sensor 100 provided in one embodiment of this application.

[0068] like Figure 2 and Figure 3 As shown, in one embodiment, the displacement sensor 100 provided in this application includes an eddy current sensing unit 10, a magnetic conductive unit 20, and a magnetization unit 30. The eddy current sensing unit 10 is connected to the processor of the 3D printer 200, and is disposed on one side of the magnetic conductive unit 20. The eddy current sensing unit 10 is used to generate eddy current effects and can sense changes in the external magnetic field, converting these changes into changes in electrical signals.

[0069] The magnetically conductive unit 20 is magnetically conductive, and its permeability is greater than that of air. The magnetically conductive unit 20 is used to guide the magnetic field lines of the eddy current sensing unit 10, making the magnetic field lines relatively concentrated to enhance the eddy current effect.

[0070] The magnetization unit 30 is located on the side of the magnetically conductive unit 20 away from the eddy current sensing unit 10. The magnetization unit 30 has a magnetic field, which is used to magnetize the magnetically conductive unit 20 and increase the magnetic flux of the magnetically conductive unit 20.

[0071] By magnetizing the magnetic permeable unit 20 with the magnetization unit 30, the magnetic flux of the magnetic permeable unit 20 can be increased, thereby enhancing the magnetic field around the eddy current sensing unit 10. A strong magnetic field can sense weak external magnetic fields; that is, within a certain range, the stronger the magnetic field, the stronger the sensing ability of the eddy current sensing unit 10 to detect the object being measured. Alternatively, it can be understood that an increase in magnetic flux allows a change in displacement to cause a larger change in magnetic flux, thus generating a larger electrical signal. Therefore, when a magnetic or metallic object (such as the nozzle 202 of the 3D printer 200) approaches the displacement sensor 100, the strong magnetic field of the eddy current sensing unit 10 can respond quickly, thereby improving the measurement sensitivity of the displacement sensor 100 provided in this application. The nozzle 202 can be metal, or the metal can be both metallic and magnetic. Simultaneously, because the eddy current sensing unit's sensing ability to detect the object being measured is enhanced, even if the distance between the displacement sensor 100 and the object being measured is far, the displacement sensor 100 can still obtain a larger signal amplitude, thus expanding the measurement range of the displacement sensor 100 provided in this application.

[0072] In one embodiment, a displacement sensor 100 is fixed to the printing platform 203 of a 3D printer 200. The displacement sensor 100 is used to detect the nozzle 202 of the 3D printer located above the printing platform 203. Since the nozzle 202 of the 3D printer 200 is made of a conductive and magnetically permeable material, the eddy current sensing unit 10 of the displacement sensor 100 can generate an eddy current magnetic field on the nozzle 202, which in turn can affect the original magnetic field of the eddy current sensing unit 10. When the nozzle 202 moves relative to the displacement sensor 100, the eddy current magnetic field changes with the displacement of both, the original magnetic field changes with the change of the eddy current magnetic field, and the electrical signal changes, thereby realizing the displacement detection of the nozzle 202 relative to the printing platform 203.

[0073] In one embodiment, the minimum distance between the eddy current sensing unit 10 and the nozzle 202 is greater than the minimum distance between the magnetic guiding unit 20 and the nozzle 202, but less than the minimum distance between the magnetizing unit 30 and the nozzle 202 in the vertical direction. That is, in the vertical direction, both the eddy current sensing unit 10 and the magnetic guiding unit 20 are located on the side of the magnetizing unit 30 facing the nozzle 202, and the upper surface of the magnetic guiding unit 20 is higher than the upper surface of the eddy current sensing unit 10. Alternatively, it can be understood that in the vertical direction, the eddy current sensing unit 10 and the magnetic guiding unit 20 are closer to the nozzle 202 than the magnetizing unit 30, and the magnetic guiding unit 20 is closer to the nozzle 202 than the eddy current sensing unit 10.

[0074] In this embodiment, by setting both the eddy current sensing unit 10 and the magnetic guiding unit 20 in the vertical direction on the side of the magnetization unit 30 facing the nozzle 202, and setting the upper surface of the magnetic guiding unit 20 to be higher than the upper surface of the eddy current sensing unit 10, that is, setting the eddy current sensing unit 10 to be housed in the magnetic guiding unit 20, it is possible to avoid the eddy current sensing unit 10 being easily contaminated or damaged by external foreign objects or collisions, thus affecting the detection.

[0075] In one embodiment, the eddy current sensing unit 10 includes a detection coil 11 for electrical connection with the processor. The magnetic guiding unit 20 includes a magnetic guiding block 21, and the magnetization unit 30 is used to magnetize the magnetic guiding block 21. The magnetic guiding block 21 has a receiving groove 211, the opening of which faces the nozzle 202. That is, the receiving groove 211 is disposed on the upper surface of the magnetic guiding block 21. The detection coil 11 is received within the receiving groove 211.

[0076] In this embodiment, a magnetically conductive block 21 is provided in the magnetically conductive unit 20 to guide magnetic lines of force, and a detection coil 11 is provided in the eddy current sensing unit 10 to sense changes in the magnetic field and convert them into changes in electrical signals. By providing a receiving groove 211 in the magnetically conductive block 21 to house the detection coil 11, it is possible to prevent the detection coil 11 from being easily contaminated by external foreign objects or damaged by collisions, thus affecting detection. On the other hand, the magnetically conductive block 21 can concentrate the magnetic lines of force around the detection coil 11, preventing the magnetic field energy of the detection coil 11 from leaking into the air, which is beneficial to improving the detection sensitivity of the displacement sensor 100.

[0077] In one embodiment, the axis of the detection coil 11 is parallel to the vertical direction.

[0078] Please refer to the above. Figure 4 , Figure 4 This is a graph showing the relationship between the magnetic permeability and the magnetic field strength of the magnetically conductive unit 20 provided in one embodiment of this application.

[0079] like Figure 4 As shown, the horizontal axis represents the magnetic field strength around the magnetically conductive unit 20, and the vertical axis represents the permeability of the magnetically conductive unit 20. In one embodiment, the magnetically conductive unit 20 is in a stage where its permeability changes rapidly when the external magnetic field changes. Alternatively, it can be understood that the initial state of the magnetically conductive unit 20 is approaching magnetic saturation or is in a state of magnetic saturation. That is, the initial state of the magnetically conductive unit 20 is... Figure 4 Point A in the diagram.

[0080] In this embodiment, the permeability of the magnetically conductive unit 20 changes drastically when the external magnetic field changes, meaning that the magnetically conductive unit 20 tends to be magnetically saturated or in a magnetically saturated state under the magnetization effect of the magnetization unit 30. Since the permeability of the magnetically conductive unit 20 in a magnetically saturated state is at its limit, the magnetization intensity of the magnetically conductive unit 20 no longer increases linearly with the magnetic field strength, but enters the nonlinear response region. When the displacement sensor 100 is relatively close to the object to be measured, the object is magnetized, and the feedback magnetic field generated by its own magnetization is superimposed on the original magnetic field of the magnetically conductive unit 20. Since the magnetically conductive unit 20 is already in a magnetically saturated state, the additional feedback magnetic field causes the permeability of the magnetically conductive unit 20 to decrease sharply, thereby causing the inductance of the eddy current sensing unit 10 to decrease rapidly, thus significantly increasing the oscillation frequency of the eddy current sensing unit 10. Therefore, a small displacement change between the displacement sensor 100 and the object to be measured can be converted into a large change in magnetic permeability, and further into a significant frequency change, forming a nonlinear amplification effect to amplify the output signal of the displacement sensor 100, thereby further improving the measurement sensitivity of the displacement sensor 100 provided in this application and expanding the measurement range.

[0081] In one embodiment, the receiving groove 211 is filled with insulating adhesive (not shown), which at least covers the detection coil 11.

[0082] In this embodiment, by providing insulating adhesive in the receiving groove 211 and wrapping it around the detection coil 11, the detection coil 11 can be fixed while also being insulated and protected.

[0083] In one embodiment, a positioning post 212 is provided in the receiving groove 211, the positioning post 212 extends vertically, and the detection coil 11 is sleeved on the positioning post 212. That is, the positioning post 212 is used to insert the inner ring of the detection coil 11.

[0084] In this embodiment, by setting a positioning post 212 in the receiving groove 211, the positioning post 212 can pre-position the detection coil 11, which is beneficial to the installation of the displacement sensor 100.

[0085] In one embodiment, the inner wall of the receiving groove 211 is annular. The annular inner wall of the receiving groove 211 fits the outer contour of the detection coil 11, thereby making the gap between the detection coil 11 and the inner wall of the receiving groove 211 smaller, allowing more magnetic lines of force of the detection coil 11 to pass through the magnetically conductive block 21, preventing magnetic lines of force from leaking into the air, thereby improving the detection sensitivity of the displacement sensor 100.

[0086] In one embodiment, the displacement sensor 100 includes a transmission line (not shown) connected between the detection coil 11 and the processor. Using a transmission line to connect the detection coil 11 and the processor facilitates the transmission of electrical signals from the detection coil 11 to the processor, which can then calculate the distance between the object to be measured and the displacement sensor 100 based on these signals.

[0087] In one embodiment, the magnetic block 21 includes a wiring groove 213 extending through the width of the magnetic block 21, the wiring groove 213 being connected to the receiving groove 211, and the transmission line being disposed in the wiring groove 213.

[0088] In this embodiment, by providing a wiring groove 213 communicating with the receiving groove 211 in the magnetic block 21, it is beneficial to fix and protect the transmission line, while also reducing the size of the displacement sensor 100. Providing the wiring groove 213 to extend through the magnetic block 21 helps to shorten the transmission distance of the transmission line and improve transmission efficiency.

[0089] In one embodiment, the cable tray 213 is provided with filler adhesive (not shown in the figure), which at least covers the transmission line. By providing filler adhesive in the cable tray 213 and covering the transmission line, the transmission line can be fixed and protected.

[0090] Please refer to the above. Figures 5 to 7 , Figure 5 This is a schematic diagram of the assembly structure of the printing platform 203 and the displacement sensor 100 provided in one embodiment of this application; Figure 6 This is an exploded structural diagram of the printing platform 203 and displacement sensor 100 provided in one embodiment of this application; Figure 7 This is an exploded structural diagram of the displacement sensor 100 provided in another embodiment of this application.

[0091] like Figures 5 to 7 As shown, in one embodiment, the displacement sensor 100 provided in this application further includes a fixing base 40, which is fixed to the middle position behind the printing platform 203 by screws. The fixing base 40 includes a mounting groove 41 with its opening facing upwards. The detection coil 11, the magnetic conductive block 21, and the magnetization unit 30 are all housed within the mounting groove 41. That is, the mounting groove 41 is used to fix and protect the detection coil 11, the magnetic conductive block 21, and the magnetization unit 30.

[0092] In one embodiment, the displacement sensor 100 provided in this application further includes a protective film 50, which is used to cover the opening of the mounting groove 41 to prevent foreign objects from contaminating the detection coil 11, the magnetic block 21 and the magnetization unit, and affecting the detection of the displacement sensor 100.

[0093] In one embodiment, the displacement sensor 100 provided in this application further includes a circuit board 60, which is disposed in the mounting groove 41 and located on the side of the magnetization unit 30 opposite to the magnetic guide block 21. That is, the circuit board 60 is located at the bottom of the magnetization unit 30. The detection coil 11 is electrically connected to the circuit board 60 via a transmission line. Specifically, the magnetic guide block 21 includes a wiring groove 213, which is located on the upper surface of the magnetic guide block 21 and communicates with the receiving groove 211. The wiring groove 213 extends along the width direction of the magnetic guide block 21. The transmission line is disposed in the wiring groove 213, and one end of the transmission line is connected to the detection coil 11, while the other end passes through the wiring groove 213 and is connected to the circuit board 60. The circuit board 60 is used to process the electrical signal of the detection coil 11 and transmit it to the processor 204 so that the processor 204 can calculate the distance between the nozzle 202 and the displacement sensor 100.

[0094] In one embodiment, the processor 204 is disposed on the circuit board 60.

[0095] In one embodiment, the circuit board 60 is used to receive the inductance change value generated by the change of the magnetic field induced by the detection coil 11, and transmit it to the processor 204. The processor 204 is used to calculate the relative displacement of the displacement sensor 100 and the nozzle 202 based on the inductance change value, so as to detect the relative displacement between the printing platform 203 and the nozzle 202.

[0096] In one embodiment, the difference between the distance between the magnetically conductive unit 20 and the nozzle 202 and the distance between the detection coil 11 and the nozzle 202 is less than the diameter of the detection coil. That is, the distance between the end face of the detection coil 11 facing the nozzle 202 and the opening of the receiving groove 211 of the magnetically conductive block 21 is less than the diameter of the detection coil 11. Or it can be understood that the difference between the upper surface of the magnetically conductive block 21 and the upper end face of the detection coil 11 is less than the diameter of the detection coil 11.

[0097] In this embodiment, the difference between the distance between the magnetic guiding unit 20 and the nozzle 202 and the distance between the detection coil 11 and the nozzle 202 is less than the diameter of the detection coil 11. This avoids the detection coil 11 being embedded too deeply in the magnetic guiding block 21, which would result in a large magnetic field distance between the detection coil 11 and the nozzle 202, affecting the detection effect. Furthermore, it prevents the detection coil 11 from being exposed outside the magnetic guiding block 21, thus avoiding leakage of the magnetic field lines of the detection coil 11 into the air and affecting the detection sensitivity.

[0098] In one embodiment, the material of the magnetically conductive unit 20 includes ferrite. That is, the material of the magnetically conductive block 21 includes ferrite. In this embodiment, based on the high magnetic permeability of ferrite, the magnetically conductive unit 20 is fabricated using ferrite, which can effectively guide and concentrate magnetic lines of force, thereby improving the measurement sensitivity of the displacement sensor 100 provided by this application.

[0099] In one embodiment, the magnetization unit 30 includes a first permanent magnet.

[0100] In this embodiment, based on the fact that the permanent magnet itself has a magnetic field, this application provides a first permanent magnet in the magnetization unit 30 to ensure that the magnetization unit 30 can magnetize the magnetic conductive unit.

[0101] In one embodiment, the magnetization unit 30 includes a first electromagnet.

[0102] In this embodiment, based on the fact that an electromagnet can generate a magnetic field after being energized, and that the magnitude and direction of the magnetic field can be adjusted by changing the magnitude and direction of the current, this embodiment of the application sets the magnetization unit 30 to include a first electromagnet, so as to ensure that the magnetization unit 30 can magnetize the magnetic conduction unit 20. At the same time, the magnetization effect on the magnetic conduction unit 20 can be controlled by adjusting the magnetic field of the magnetization unit 30.

[0103] In one embodiment, the object to be tested includes a magnetically conductive material. For example, the nozzle 202 is made of a magnetically conductive material.

[0104] In this embodiment, based on the magnetic permeability of the magnetic material, this application sets the object under test as a magnetic permeable material. When the displacement sensor 100 moves relative to the object under test, the magnetic field around the eddy current sensing unit 10 can magnetize the object under test, so that the object under test forms a feedback magnetic field. The feedback magnetic field of the object under test can in turn affect the magnetic field of the eddy current sensing unit 10, thereby realizing displacement detection.

[0105] In one embodiment, the object to be tested includes a second permanent magnet.

[0106] In this embodiment, based on the magnetic field inherent in the permanent magnet, this application sets a second permanent magnet in the object to be tested to ensure that the object to be tested can affect the magnetic field of the eddy current sensing unit 10 when it is close to the displacement sensor 100, thereby realizing displacement detection.

[0107] In one embodiment, the object to be tested includes a second electromagnet.

[0108] In this embodiment, based on the fact that an electromagnet can generate a magnetic field after being energized, and that the magnitude and direction of the magnetic field can be adjusted by changing the magnitude and direction of the current, this embodiment of the application sets the object under test to include a second electromagnet to ensure that the object under test can affect the magnetic field of the eddy current sensing unit 10.

[0109] In one embodiment, the magnetic field direction of the magnetization unit 30 is the same as the magnetic field direction of the object under test.

[0110] In this embodiment, by setting the magnetic field direction of the magnetization unit 30 to be the same as the magnetic field direction of the object to be measured, when the displacement sensor 100 and the object to be measured are relatively close, the magnetic field of the magnetization unit 30 and the magnetic field of the object to be measured can be superimposed to a large extent to enhance the magnetic field strength around the eddy current sensing unit 10, thereby causing the magnetic permeability of the magnetic permeable unit 20 to drop sharply.

[0111] In one embodiment, the positioning post 212 and the magnetic block 21 are an integral structure.

[0112] In this embodiment, the positioning post 212 and the magnetic block 21 are integrated into one structure, which simplifies the installation of the displacement sensor 100 and also enables the positioning of the detection coil 11 by using the positioning post 212.

[0113] It should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0114] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0115] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Those skilled in the art will understand that implementing all or part of the processes of the above embodiments, and making equivalent changes according to the claims of this application, still falls within the scope of this application.

Claims

1. A displacement sensor suitable for a 3D printer, the 3D printer including a processor, characterized in that, The displacement sensor includes: The eddy current sensing unit is connected to the processor of the 3D printer; A magnetic permeable unit, wherein the magnetic permeability of the magnetic permeable unit is greater than that of air, and the eddy current sensing unit is disposed on one side of the magnetic permeable unit; A magnetization unit is disposed on the side of the magnetically conductive unit away from the eddy current sensing unit, so as to magnetize the magnetically conductive unit.

2. The displacement sensor according to claim 1, characterized in that, The displacement sensor is fixed to the printing platform of the 3D printer, and the displacement sensor is used to detect the nozzle of the 3D printer located above the printing platform; In the vertical direction, the minimum distance between the eddy current sensing unit and the nozzle is greater than the minimum distance between the magnetic guiding unit and the nozzle, and the minimum distance between the magnetic guiding unit and the nozzle is less than the minimum distance between the magnetizing unit and the nozzle.

3. The displacement sensor according to claim 1, characterized in that, The magnetic guiding unit includes a magnetic guiding block, the eddy current sensing unit includes a detection coil, the magnetic guiding block has a receiving groove, the opening of the receiving groove faces the nozzle of the 3D printer, and the detection coil is received in the receiving groove.

4. The displacement sensor according to claim 3, characterized in that, The receiving groove is filled with insulating adhesive, which at least covers the detection coil.

5. The displacement sensor according to claim 3, characterized in that, The receiving slot is provided with a positioning post, which extends vertically, and the detection coil is sleeved on the positioning post.

6. The displacement sensor according to claim 3, characterized in that, The displacement sensor includes a transmission line connected between the detection coil and the processor.

7. The displacement sensor according to claim 6, characterized in that, The magnetic block includes a wiring groove, which is connected to the receiving groove, and the transmission line is disposed in the wiring groove.

8. The displacement sensor according to claim 7, characterized in that, The wiring groove runs through the width of the magnetic block.

9. The displacement sensor according to claim 7, characterized in that, The cable tray is filled with adhesive, which at least covers the transmission line.

10. The displacement sensor according to claim 7, characterized in that, The displacement sensor includes a circuit board, which is disposed on the side of the magnetization unit away from the magnetic conductive unit; The detection coil is connected to the circuit board via the transmission line, and the circuit board is connected to the processor.

11. The displacement sensor according to claim 3, characterized in that, The difference between the distance between the magnetic conductive unit and the nozzle and the distance between the detection coil and the nozzle is less than the diameter of the detection coil.

12. The displacement sensor according to claim 3, characterized in that, The magnetization unit includes a first permanent magnet or a first electromagnet.

13. The displacement sensor according to claim 12, characterized in that, The first permanent magnet or the first electromagnet is attached to the magnetic block.

14. The displacement sensor according to claim 1, characterized in that, The material of the magnetically conductive unit includes ferrite.

15. The displacement sensor according to claim 1, characterized in that, The material of the magnetically conductive unit includes soft magnetic materials or hard magnetic materials.

16. The displacement sensor according to claim 1, characterized in that, The material of the magnetically conductive unit includes metallic magnetic materials.

17. The displacement sensor according to claim 1, characterized in that, The material of the magnetically conductive unit includes powdered magnetic material.

18. The displacement sensor according to claim 1, characterized in that, The magnetic permeability of the magnetic permeable unit changes drastically when the external magnetic field changes.

19. A 3D printer, characterized in that, It includes a processor, a nozzle, a printing platform, and a displacement sensor as described in any one of claims 1-18, wherein the processor is electrically connected to the displacement sensor.

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